The trick is to have a flexible routing matrix with multiple outputs: one should be tapped before processing (this can also be achieved directly from the DAW using a separate output and a separate D/A output), one should be a copy of the processed analog signal, and then of course a processed signal that returns to the A/D.

On the monitor controller you switch between the inputs to listen to the signal at various points in the chain. Sometimes the routing matrix and monitor controller functionality is combined in a console, but the concept is the same.

The above illustration is a simplified version of my own setup, where the AD/DA is the Lynx HiLo (the HiLo has both main AD/DA and a separate monitoring DAC), the routing matrix is the Dangerous Music Liaison, and the monitor controller is the Danfield Monitor2. I'll probably make a more complete version of this flowchart when I have time.

This allows me to:

1) Listen to the original signal from the DAW prior to any processing. This signal can also be a gain compensated copy for comparison purposes.2) Monitor the full chain with both digital and analog processing3) Monitor the post D/A but pre-analog processing chain4) Monitor the post analog but pre-A/D chain

I have more options, but I don't use those. Apart from option 1 which requires a mouse or keyboard action, all are achieved directly on the monitor controller without the need to set up anything else.